DMR, APCO, NXDN, MOBITEX-2000,

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amateurRadio
Posts: 2
Joined: Sun Nov 15, 2015 5:42 pm

DMR, APCO, NXDN, MOBITEX-2000,

Post by amateurRadio » Sun Nov 15, 2015 6:00 pm

Dear All,

Here goes a basic problem with these signal types.
I want to classify DMR, APCO, NXDN, MOBITEX-2000
signals. However I do not even know how these signals
appear on the spectrum(I have an SDR by which I record signals,
however such signals are not used in our region.)
The classification method by which I want to proceed, is to
demodulate and find patterns in the demodulated versions.
Specifically, let's continue with DMR signal. I have written
a code as a C4FM demodulator for this signal type, and I am looking
for a pattern within the signal. But however there is no high
SNR, correct version signal on the web to check my demodulator with.

As you might know these signals are sent with FM transmitter.

Is it possible for you to share with me some signals files with the following
requirements?
for example for DRM:
I want an FM signal which is recorded as a two channel signal(real and imag)
FM demodulated version of the same signal which is recorded as a
single channel signal(real signal).


Regards,

rtlsdrblog
Site Admin
Posts: 2774
Joined: Mon Nov 19, 2012 11:54 pm

Re: DMR, APCO, NXDN, MOBITEX-2000,

Post by rtlsdrblog » Mon Nov 16, 2015 12:31 am

Check out sigidwiki.com, you might find some samples there, but not many IQ files are there yet.

amateurRadio
Posts: 2
Joined: Sun Nov 15, 2015 5:42 pm

Re: DMR, APCO, NXDN, MOBITEX-2000,

Post by amateurRadio » Mon Nov 16, 2015 7:32 am

rtlsdrblog wrote:Check out sigidwiki.com, you might find some samples there, but not many IQ files are there yet.
I have used those signals , but those signals are baffling.
Spectrum of the signal lies in the low pass and it is not clear
how the signal is recorded.

I just want some expert that encounters this signal type
on air records them, so that I am assured the signal is not
recorded in the wrong way.

rtlsdrblog
Site Admin
Posts: 2774
Joined: Mon Nov 19, 2012 11:54 pm

Re: DMR, APCO, NXDN, MOBITEX-2000,

Post by rtlsdrblog » Mon Nov 16, 2015 9:35 pm

It's quite hard to share IQ files because they get very big, even just for a few second of recording. You might try contact the people making DSD or DSD+ or Unitrunker. They probably have some sources that they use during development of their software.

AmatorRadioResearch
Posts: 7
Joined: Tue Aug 09, 2016 10:30 am

Re: DMR, APCO, NXDN, MOBITEX-2000,

Post by AmatorRadioResearch » Mon Jan 16, 2017 6:04 pm

Most of the DMR signals on sigidwiki are corrupted versions.
They recorded the signal, but in the wrong way.
Technically they have not maintained the Nyquist rate and so on.

Many thanks to you.
I found a way to record my signals.

I used one the radios with DMR protocol, and
recorded the signal with funcube dongle.

It is easy to record the signal Real and in I/Q format.
please feel free to contact me at [email protected] if you
face up with similar problem.

AmatorRadioResearch
Posts: 7
Joined: Tue Aug 09, 2016 10:30 am

Re: DMR, APCO, NXDN, MOBITEX-2000,

Post by AmatorRadioResearch » Mon Jan 16, 2017 6:07 pm

Sorry to add that , I have forgotten my password to AmateurRadio,
Thereby, both of amatorradioresearch and AmateurRadio usernames
are for me :D :D :D :D

rtlsdrblog
Site Admin
Posts: 2774
Joined: Mon Nov 19, 2012 11:54 pm

Re: DMR, APCO, NXDN, MOBITEX-2000,

Post by rtlsdrblog » Wed Jan 18, 2017 9:20 am

The audio files on sigidwiki are probably mp3 compressed which may break digital decoding, but they're mainly there to give you an audio idea of what they actually look and sound like.

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